One section of a conventional continuous casting line is illustrated in FIG. 1. Initially, molten steel is supplied to a continuous caster 10 that produces a cast steel strand 12. After the strand 12 exits the caster 10, the strand 12 is cut to length with a cutter 16 to produce a series of cast slabs 18 that are discharged to a rolling table 14. Subsequent to being severed from the strand 12, each slab 18 is transversely fed into a reheat furnace 15 using a transfer machine 20.
The reheat furnace 15 brings the slab 18 to a uniform temperature to facilitate rolling. Upon exiting the reheat furnace 15, the slab 18 is transferred to an upstream end of the rolling table 14. The slab 18 is then descaled in one or more descalers 24, 26, which apply a series of high-pressure waterjets/sprays onto the surface of the slab 18 to remove scale. The slab 18 is then processed by a reversing rolling mill 28. The rolling mill 28 is typically provided with upstream and downstream coiler furnaces 30, 32. Upon reaching a desired thickness in the rolling mill 28, the intermediate product 34 (also referred to as a strip) continues downstream to further processing (not shown). Downstream processing may include shearing the ends of the intermediate product 34, cutting the intermediate product 34 to length and/or coiling the intermediate product 34 into coils.
A Steckel mill is one of the various types of rolling mills, an example of which is illustrated in FIG. 2. This type of reversing rolling mill 28 typically passes the slab 18 through rollers 36, 38 several times to reduce the slab 18 to a strip (or intermediate product) 34 having a thinner thickness. The reversing rolling mill 28 also maintains the strip 34 at a relatively high temperature so as to produce a desired steel microstructure. Because the rolling reduction typically requires more than one or more passes through the rollers 36, 38, coiler furnaces 30, 32 are typically installed in-line with the reversing rolling mill 28 to maintain the temperature of the strip 34 between passes through the rollers 36, 38. One coiler furnace 30 is upstream of the rollers 36, 38 and a second coiler furnace 32 is downstream of the rollers 36, 38.
Each coiler furnace 30, 32 includes an internal rotatable generally-cylindrical drum 44, 46, generally known as a coiler drum. In operation, the leading edge, for a particular pass, of the strip 34 emerging from the rollers 36, 38 that requires further passes through the rollers 36, 38 is directed into the nearer coiler furnace 30, 32 and wound onto its respective coiler drum 44, 46. Subsequently, the strip 34 is unwound from the coiler drum 44, 46 as the strip 34 is fed back through the rollers 36, 38 for a further pass. If further rolling in the reversing rolling mill 28 is required, after the next pass through the rollers 36, 38, the strip 34 is wound onto the coiler drum 44, 46 of the coiler furnace 30, 32 on the other side of the rollers 36, 38.
FIG. 3 illustrates a conventional coiler drum 50, and the work surface 52 of the conventional coiler drum 50 is the portion of the coiler drum 50 that contacts the plate, strip, etc. of steel. With a conventional coiler drum 50, the work surface 52 is smooth or flat. However, a problem associated with a coiler drum 50 having a smooth work surface 52 is that the work surface 52 tends to accumulate detritus matter, such as scale and other debris, from the strip or refractory from the lining of the furnaces 30, 32. This unwanted material can be reintroduced onto the strip as a surface defect that can cause of portion of the strip to be undesirably scrapped, reworked or reclassified as a lower quality product.
One solution to this problem is to add channels 64 into the work surface 62 of the coiler drum 60, as illustrated in FIG. 4. These channels 64 are cut into the coiler drum 60 continuously from one end 66 of the coiler drum to the other end 68 and allow the unwanted material to accumulate within the channels 64. The strip, however, is still in contact with about 75–85% of the original surface 62 of the coiler drum 60, and it has been determined that notwithstanding the channels 64, the detritus material still accumulates on the work surface 62 of the coiler drum 60. Thus, there is a need to provide an improved coiler drum that reduces or eliminates that amount of detritus material that is reintroduced onto a strip.